Inflammatory bowel disease is generally linked to a decrease in gut bacteria diversity, but new research suggests it could also be correlated with an increase in the diversity of viruses.
Researchers found patients with inflammatory bowel disease tended to have a greater variety of viruses in their digestive systems than healthy patients, Washington University in St. Louis reported. This suggests these viruses could be contributing to the development of the disease.
The new research is the first to link the disease with changes in the virome, as opposed to exclusively bacteria. The findings suggest viruses could play unexpected roles in other conditions such as obesity and diabetes.
"This is the tip of the iceberg," said senior author Herbert W. Virgin. "A significant portion of the viral DNA we identified in these patients is unfamiliar to us - it comes from newly identified viruses we don't know much about. We have a great deal of groundwork to do, including sequencing the genetic material of these viruses and learning how they interact with the gut and gut bacteria, before we can determine if changes in the virome cause these conditions or result from them."
The researchers studied three groups of patients with Crohn's disease or ulcerative colitis living in Chicago, Boston and the United Kingdom. They compared viral DNA taken from fecal samples of the participants with those extracted from healthy patients from the same areas.
"Much of the increased viral diversity in participants with inflammatory bowel diseases was in the form of bacteriophages, which are viruses that infect bacteria and can incorporate themselves into the bacteria's genetic material," said Virgin.
The researchers hope the findings will help lead to new treatments for inflammatory bowel disease. The team is now working on an animal model of inflammatory bowel diseases in hopes of further determining what is causing the illnesses.
"We know that mutations in human genes affect the risk of inflammatory bowel diseases, and scientists also are exploring how bacterial genes may influence risk," Virgin said. "Our results show that the virome's potential effects on the gut also need to be a part of these investigations."
The findings were published in a recent edition of the journal Cell.
